What's a fatberg?

A fatberg is defined as a very large mass of solid waste in a sewerage system, consisting of things such as of congealed fat, oils and sanitary products that have been put down the drains or flushed down the toilet.

Quietly expanding day after day, the congealed rancid masses of human waste, fat, oil and wet wipes are menaces, unique to 21st century living. Capable of breaking the sewage system, their threat lies in the ability to wreak sewage havoc in homes and businesses.

Sewers designed only for water, toilet paper and human waste are increasingly used as a rubbish bin. The sewer system simply cannot cope.

As more and more ’unflushables’ (items that should not be flushed) get thrown into the drains, the more a fatberg grows. Wipes, condoms, sanitary products and cotton wool, stick to the gluey mass and as it builds up, meaning less waste can pass through the pipe. Eventually, this can cause major blockages in the sewage network and if the sewage can’t reach our waste treatment works, it is forced back up to where it came from.

See what it's like to come across a fatberg in a sewer.

Fatberg Discoveries

A huge 40-tonne fatberg was discovered in blocking a sewer in South London. It was cleared following a heroic effort by our engineers, who even pulled out some of the monster blockage with their hands.

The mass, which weighed the same as three red buses, was clogging up an underground sewer in Greenwich and took three weeks to clear, using a combination of high-powered water jets to blast the blockage loose and removing the debris by hand.

They pulled out tonnes of fat, grease and other material as they battled the fatberg, which at points had taken up 80 per cent of the sewer’s capacity. If left, it could have grown even bigger and caused problems in the waste network, including sewage backing up in to homes and businesses.

The Whitechapel Fatberg

The famous Whitechapel fatberg, discovered in September 2017, was the largest ever found in the sewerage system. And it is for this grossly unique reason it attracted attention from around the globe, with stories of its sheer beastliness featuring in the media.

It is thanks to the high media profile, over several weeks, that it was christened with a name, after a public vote was created resulting in the beast being rather affectionately called ‘Fatty McFatberg’.

The sheer scale of ‘Fatty McFatberg’ was what made it such a gruesome spectacle. More than twice the length of two Wembley football pitches, it weighed- the same as 11 double decker buses.

Fatty was blocking a stretch of original Victorian sewer and was very difficult to remove.

Eliminating the fatberg took a team of eight, working every day for several weeks. Using high powered jet hoses, they painstakingly broke up the mass averaging 20 to 30 tonnes on each shift. Fatty McFatberg was then sucked out by tankers and taken away to be recycled in Stratford.

Preventing Fatbergs

To reduce the risk of fatbergs forming in the future, we all have a responsibility to ensure only the 3Ps are flushed down the loo - pee, paper and poo!

Cooking oils and fats need to be left to cool and solidify before being disposed of in the bin, instead of putting them down the drain. If in doubt, remember to bin it – don’t block it.

The future of fatbergs

Leading waste to power firm, Argent Energy, has teamed up with us to transform our fatbergs into pure green fuel.

Our plans mean that Fatty McFatberg can be converted into around 10,000 litres of biodiesel, a renewable fuel that is created from re-using cooking oils and blending with petroleum diesel to make a recycled fuel to power engines.